System of electrical distribution.



No. 791,938. v PATENTED JUNE 6, 1905. I

G. B. PALMER.

SYSTEM OF ELECTRICAL DISTRIBUTION. APPLICATION rum) JULY 5. 1904.

2 SHEETS-SHEET 1- L/- V I? WM wwiz if No. 791,938. PATENTED JUNE 6,1905.

G. E. PALMER. 3

SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION TILED JULY 5. 1904.

2 SHEETS-SHEET 2.

' I Ffiorrzgpi UNITED STATES Patented June 6, 1905.

PATENT OFFICE.

GRANVILLE E. PALMER, OF BOSTON, MASSACHUSETTS, ASSIGNOR OF ONE- HALF TOOHAItLES B. PRICE AND FRANK S. PRICE, OF BOSTON, MAS- SAOHUSETTS.

SYSTEM OF ELECTRICAL DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 791,938, dated June 6,1905.

Application filed July 5,1904. Serial No. 215,251. I

To a whom it may concern.-

Be it known that I, GRANVILLE E. PALMER, ofBoston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Systems of Electrical Distribution, of which thefollowing is a sgeciiication.

This invention has relation to systems of electrical distribution inwhich alternating Io currents of high voltage are employed for lightingor other purposes.

The object of the invention is to safeguard the public from danger oflive wires and to protect against injury the apparatus forming a part ofthe system in case of a broken wire or a short circuit. This in ageneral way is accomplished by automatically (ilevitalizing open orbroken circuits and by automatically cutting out from the generatorthose circuits in which there is an overload injurious to the generatoror other apparatus.

The invention may be embodied in a system having a single or multiphasealternating-current circuit of two or more wires operating 2 5 inconnection with a system of series alternating-current arc-lamps inwhich constantcurrent transformers are interposed between the generatorand the lamps.

Where open-circuit or short-circuit condi- 3 tions occur in distributingsystems, such as hereinbefore referred to, special apparatus isnecessary to insure the protection of the translating devices formingpart of the system. The present invention is in part designed to pro- 35 duce a combined overload and underload circuit-breal ing device inwhich the use of springs and a multiplicity of levers and intricatelocking devices is avoided and in which the switch or make-and-breakdevices are in 4 their simplest form and are sufficient in themselves toopen circuits of practically any potential, amperage, and power factorwith which the engineer has to deal in the operation of high-tensionalternating-current circuits.

In the operation of constant-current transformers an open circuit in thesecondary or lamp circuit will cause a rise of potential in saidlamp-circuit far in excess of the maximum full-load voltage, and a shortcircuit, 5 particularly if it be of a periodic nature, will cause aviolent oscillation of the movable members of the constant-currenttransformer that is highly detrimental to said transformer.

T0 promptly protect these distributing systerns against open circuits,it is necessary that the breaking apparatus be so constructed that thatelement which performs the function of releasing the locking mechanismhas no other function that may interferevith this service, 50 and itmust be likewise so designed that no magnetic lag interferes with itsproper operation, and it must also be capable of such arrangement thatit will operate at the moment the charge of the line falls below thecapacity 5 thereof, whereby the primary side of the line may be openedbefore the secondary is dis-- charged at an increasing potential. Toaccomplish this, it has been found desirable to use an electromagneticmechanism with the 7 fewest possible number of ampere-turns compatiblewith the work it is desired to perform. The relative position of thearmature to the solenoid is such that practically the full currentstrength of the circuit is necessary to primarily attract said armatureand the magnetic relation between the solenoid and armature is then suchthat a predetermined diminution of the current strength will so reducethe magnetic field that the armature will fall and perform itsfunctions.

I regard it as desirable and practically essential in disconnecting aconstant-current transformer from its source of supply in the event ofopen or short circuit condition in its 5 secondary circuit that theprimary side be broken before the secondary is discharged.

Referring to the drawings, which illustrate several embodiments of theinvention, Figure 1 represents in front elevation a portion of 9 theswitchboard and represents the mechanical features of an apparatusembodying the invention. Fig. 2 represents a side elevation of the same.Fig. 3 represents, diagrammatically, a system of electrical distributionemploying a constant-current transformer located between the source ofsupply and the arc-lights or other translating devices.

Referring first to Figs. 1 and 2, 1O indi dicates a switchboard orbase-plate upon the rear of which is supported a make-and-break deviceconsisting of an oil-switch, (indicated as a whole at 11.) The movablecontacts 12 are operated by a handle-lever 13. The raising of the levercloses the switch and its dropping opens it. 14 represents avertically-movable catch-bar arranged to slide in guides 15 16,projecting forwardly from a plate 17, secured to the front face of theswitchboard 10. This catch-bar is connected to the handle-lever 13 by alink 18. The inner face of the catch-bar 14 is notched to form ashoulder 19, which when the handle-lever 13 is raised may be engaged bythe hooked end of a latch 20. The said latch projects downwardly from ashaft 21, journaled in ears or lugs 22, formed in the plate 17. Securedto said shaft 21 are two arms projecting horizontally-in oppositedirections, the forwardly-projecting arm being indicated at 23 and therearwardly-pro jecting arm at 24. The latter passes through an aperturein the switchboard 10 and is pro vided with a weight 25, which holds thecatch forwardly, so that it may engage and support the catch-bar 14. Theupper end. of the catch-bar is beveled and the hooked end of the latchis beveled, so that when the handle 13 is raised the latch will beforced rearwardly until it registers with the notch in the catchbar,upon which the hooked end of the latch will slip under the notch of thelatch 19 and prevent the catch-bar and the handle from dropping bygravity. When the latch is moved rearwardly to release the catch-bar,the weight of the handle and the catch-bar are sufficient to immediatelyopen the switch by moving the movable contacts away from the stationarycontacts. Supported upon the rear face of the switchboard 10 there is anelectromagnetic actuator comprising a solenoid 26. It is locatedimmediately below the arm 24, so that a projection 27 on said arm eX-'tends part way into the cylindrical aperture therein. The plunger orcore 28 when the current through the solenoid increases beyond a givenstrength rises and engages the pro jection 27 of the arm 24 with a sharphammer-blow and disengages the latch 20 from the catch-bar 14.

The plunger 28 when in its lower position rests in a tubular casing 29.attached to the solenoid and having in its lower end an adjustableabutment 30. The solenoid or electromagnet and its core or armatureconstitute an overload-release or switch-controlling mechanism, as willbe explained, which acts directly upon the integral structure whichconstitutes the latch for releasing the switchlever 13 and the catch-bar14 connected thereto.

Located directly over the arm 23, which has a handle 31, by which it maybemanually operated, is an electromagnetic switch-controller. Itconsists of two solenoids or coils 32 32, the plungers 33 of which areconnected together in the form of a yoke. Loosely connected to theplungers or armatures 33 by a strap 34 and screw 35, so as to have acertain amount of lost motion relatively thereto, is a plunger 36,weighted as at 37. This plunger is directly over the arm 23, so thatwhen it is permitted to drop it engages the arm 23 with a hammer-blowand disengages the latch 20 from the catch-bar 14.

The electromagnetic mechanisms comprising the coils 32, the armatures33, and the weighted plunger 36 constitute an underloadrelease mechanismfor effecting the automatic opening of the switch 11.

In conjunction with the underload-release mechanism I employ mechanismfor automat= ically notifying the engineer or attendant of the openingof the switch. This mechanism consists of a signal 38, placed in acircuit 39, said circuit including a generator 40, a stationary contact41, and a movable contact 42, so located as to be raised by the weight37 upon the plunger 36. When the plunger drops, the two contacts closethe circuit 39. Placed in the circuit are two opposed contacts 43 43,through which the circuit may be opened by a removable plug 44.

Referring to Fig. 3, which illustrates diagrammatically a system inwhich the mechanism as herein described is utilized, a indicates analternating generator, and b the main or primary circuit in which islocated the switch 0, corresponding to that at 11 in Fig. 2. (1indicates a constant-current transformer having the primary coil 6 andthe secondary coils 03 The inner end of the coil cl and the inner end ofthe coil (Z are connected in series with a working circuit 0, having alightning-arrester f and a series of translating devices, (as thearc-lamps at g.) The outer ends of the two coils cl (Z are connected inseries with a second working circuit 6', having a lightning-arrester fwith translating devices, (as the arc-la'mps g.) In series .in the maincircuit 6 is the overload-release magnet 26, and in the working circuita, is placed the underload-release magnet 32, these numerals 26 and 32indicating conventionally in Fig. 3 the elements which are graphicallyshown and indicated by the same numerals in Figs. 1 and 2.

It will be noted that the coils of the overload-release magnet areinterposed in the main or primary circuit 6, whereas the coils of theunderload-release magnet are in the secondary circuit, and that theunderload-release mechanism and the overload-release mechanism operatedirectly upon the main switch or make-and-break device placed in theprimary or main circuit to instantly disconnect the constant-currenttransformer d from the source of supply, when the current falls to apredetermined point or rises above another predetermined point, so thatthe primary side broken before the secondary is discharged.

In the systems herein described the switches are held in closed positionby mechanical contrivances and not by a magnetic pull, so that thearmatures do not in any manner hold the switches closed, but, on thecontrary, operate only to effect their release. Again, in said systemthe armatures of both the underload and the overload release magnetsoperate directly upon elements connected rigidly to the latches, so thatsaid armatures therefore act practically directly on said latcheswithout the aid of springs or other uncertain or unstable media. Thelatch is also pivoted or mounted on a rock-shaft and engages the catchon the movable contact. The arms on the rockshafts project in oppositedirections and are each moved by a sharp or hammer blow, whereby therelease of the switch is rendered certain.

Having thus explained the nature of the invention and described a way ofconstructing and using the same,although Without attempting to set forthall of the forms in which it may be made or all of the modes of its use,I declare that what I claim is 1. In a system of electricaldistribution, a primary alternating-current circuit, a secondarycircuit, a constant-current transformer, a switch in the primarycircuit, an underloadrelease mechanism in the secondary circuit, anoverload-release mechanism in the primary circuit, and means by whicheach of said mechanisms causes the opening of said switch.

2. In a system of electrical distribution, a primary alternating-currentcircuit, a secondary circuit, a constant-current transformer, a switchin the primary circuit, an underload mechanism in the secondary circuit,and means by which said underload mechanism causes the opening of saidswitch upon the diminution of the current in the secondary circuit to apredetermined point.

3. In a system of electrical distribution, a primary alternating-currentcircuit, an induced-current or secondary circuit, a selfopening switchin said primary circuit, and an underload-release electromagneticmechanism in series in said secondary circuit for causing said switch toopen upon the diminution of the current in said secondary circuit to apredetermined point, said electromagnetic mechanism comprising a coil, aplunger extending into said coil, and a latch for the switch arranged inrelation to the plunger, whereby it is given a hammer-blow to releasethe switch by said plunger when there is a sufficient diminution ofcurrent in the secondary circuit.

4. In a system of electrical distribution, a primary alternating-currentcircuit, an induced-current or secondary circuit, a selfopening switchin said primary circuit, an underload-release electromagnetic mechanismin series in said secondary circuit for causing said switch to open uponthe diminution of the current in said secondary circuit to apredetermined point, and an overload release mechanism in the primarycircuit for causing said switch to open upon an excess of current insaid primary circuit.

In testimony whereof I have affixed my signature in presence of twowitnesses.

GRANVILLE E. PALMER.

Witnesses:

M. B. MAY, C. C. STnoHER.

